Age-specific seroprevalences of merkel cell polyomavirus, human polyomaviruses 6, 7, and 9, and trichodysplasia spinulosa-associated polyomavirus.

Six new human polyomaviruses have been identified since 2008 (Merkel cell polyomavirus [MCPyV], human polyomavirus 6 [HPyV6], HPyV7, HPyV9, trichodysplasia spinulosa polyomavirus [TSPyV], and Malawi polyomavirus [MWPyV]). The presence of specific antibodies against MCPyV, HPyV6, HPyV7, HPyV9, and TSPyV in 828 Italian subjects aged 1 to 100 years was investigated by virus-like particle-based enzyme-linked immunosorbent assays (ELISAs). The findings indicate that all of these new polyomaviruses circulate widely in humans, with seroprevalences in adulthood ranging from 39.4% for HPyV9 to 87.1% for MCPyV, and that primary exposure is most intense in childhood, with the exception of HPyV7 and HPyV9, for which the seroprevalence increased throughout life. The proportion of subjects with high antibody titers was found to increase with age for MCPyV and to decrease with age for TSPyV.

Specific antibodies reacting with simian virus 40 capsid protein mimotopes in serum samples from healthy blood donors.

Simian virus 40 (SV40), a small DNA tumor virus, was inadvertently administered to human populations with the use of contaminated vaccines. SV40 sequences have mainly been detected in healthy individuals and cancer patients using polymerase chain reaction techniques. However, some studies have failed to reveal the presence of SV40 in human specimens. These conflicting results indicate the need for new research to verify whether SV40 is circulating in humans. Mimotopes from SV40 structural peptides were tested to investigate for specific reactions to human sera antibodies. An indirect enzyme-linked immunosorbent assay with synthetic peptides from SV40 viral capsid proteins 1-2-3 (VPs 1-2-3) was set up and employed to test 855 serum samples from healthy blood donors. Data from immunologic assays indicate that serum antibodies against SV40 VP mimotopes are detectable, although with a low titer, in blood donors 18 to 65 years old. The overall prevalence of serum samples that reacted with the 2 SV40 VP peptides was 18%. The strong points for this novel method include the simplicity of its approach and the potential to discriminate between SV40-specific antibody responses and to draw correlations between responses to the 2 independent SV40 peptides. These data suggest that SV40, or a yet undetected closely related polyomavirus, is circulating in human populations, but with lower prevalence than that of the ubiquitous BK and JC human polyomaviruses.